Vehicle frames may include a variety of beams that make up structure of the vehicle. Cross beams may extend between longitudinal frame rails to provide sufficient resistance to side impacts. Pillars are beams that support the vehicle roof and resist crush loads. Bumper support beams extend between a vehicle frame and front or rear bumpers to absorb energy associated with front or rear impacts. More stringent fuel and emissions standards have created the need to reduce the weight of vehicles. However, vehicle safety standards and ratings require strengthening of beams to increase absorption of energy and improve crash performance. Stronger lighter-weight materials have been incorporated in vehicles by primarily changing the materials of the beams. But changing to lightweight materials may not be sufficient to minimize weight and improve crash worthiness.
A beam incorporating a number of cells disposed between inner and outer walls of the beam may not provide sufficient stiffness or energy absorption. An improperly designed beam may have poor initial stability, resulting in a single or double buckling hinge within a portion of the column or beam that is spaced apart from the application point of the load. Other designs may result in a stable crush, but they may have a low slenderness ratio and thus have large and non-uniform folding lengths. Generally, a stronger beam requires a beam with larger outer perimeter or cross-section, this may present a challenge for using the beam in relatively small or compact areas. Moreover, a range of strength requirements may require various beams having various outer dimensions. This may lead to a more complex and complicated design.
The present disclosure is directed to achieving fuel economy driven weight reduction in vehicle beams and structural walls while maximizing compressive strength and energy absorption during a crash. This disclosure is also directed to providing a consistent set of beams having various strengths and fewer variations of the outer dimensions.